Patent GB-1210671-A (GB)
Title: Additional air control device in combination with the carburetter of an internal combustion engine
IPC: F02M23/12
Filed: 1967-11-09
Abstract: 1,210,671. Treating I. C. engine charge. ATOX TRUST REG. Nov. 9, 1967 [May 20, 1967; May 23, 1967; Aug.18, 1967], No.50956/67. Heading F1B. A device mounted between the carburetter and intake manifold of an I. C. engine comprises two plates 1 and 2 in face-to-face relationship and having an aperture therethrough for the passage of combustible mixture. The device includes two regulating devices, at least one of which has a piston and cylinder 7 for admitting air via a duct 12 to a port 13 communicating with the plate aperture. A port 6 communicating with the plate aperture is connected to the cylinder 7 through a duct 5 to transmit the vacuum in the aperture thereto to operate the piston. A constriction (18), Fig. 3 (not shown), is provided in the plate aperture and air flowing through the port 13 atomises condensate from the mixture which collects thereon. Air is also admitted to the plate aperture through a duct 3 and port 4. A second piston and cylinder air regulator 8 communicating with the port 13 and the port 6 may operate to supply air to the plate aperture at a vacuum greater than that necessary for operation of the first regulator. The first regulator may operate with the engine overrunning at about 1500 r.p.m. and the second at 2000 to 2500 r.p.m. The pistons of the regulators are spring-biased and the piston of one of the devices may close an electrical contact to energize the coil of a magnetically actuated valve to close the carburetter idling jet. The piston of the regulator 8 may be moved mechanically to supply air when the carburetter throttle valve has reached a certain opening. The second air regulator may be a throttle valve controlled by an electromagnet (31), Fig.4 (not shown), actuated in response to an electrical signal of a comparison between the vacuum in the plate aperture and the position of the carburetter throttle valve. A device including a potentiometer tap-operating membrane may measure the vacuum in the plate aperture and supply the result to an amplifier (24), Fig. 5 (not shown), including a temperature compensator (36). The output of the amplifier (24) is connected to a second amplifier, e.g. a thyristor, connected to the coil (30), Fig.4, of the electromagnet (31). The amplifier (24) may be supplied with a signal corresponding to engine speed. The air throttle valve may be operated such that it has a certain opening at certain engine speeds at normal engine load. When the carburetter throttle valve setting is greater or smaller than the setting at normal load at the prevailing speed there is a corresponding decrease or increase respectively in the setting of the air throttle valve. This air throttle operation occurs at about 2, 200 r.p.m. when the engine is running under load. In a further embodiment, Figs. to 9 (not shown), the air throttle valve (43) is biased closed by a pretensioned spring (45) and a force acting in the opening direction is provided by an armature (41) on the valve shaft (42) acted on by an electromagnet (46). The electromagnet (46) is energized by a winding (48) fed from a dynamo or magneto (50), belt driven by the engine, or the engine ignition coil. The force of the electromagnet (46) exceeds the pretension of the spring (45) at engine speeds above 2,000 r.p.m. The air throttle valve (43) may be operated with a certain lag after operation of the carburetter throttle valve 52.